INFORMATION RECORDING DEVICE, INFORMATION REPRODUCING DEVICE, INFORMATION RECORDING METHOD, INFORMATION REPRODUCING METHOD, AND INFORMATION RECORDING MEDIUM, AND PROGRAM PROVIDING MEDIUM

摘要

PROBLEM TO BE SOLVED: To attain efficient key revision processing by executing key distribution through an encryption key distributing configuration adopting a tree structure. SOLUTION: A revision state of a master key and a media key employing a key distribution configuration adopting a tree structure is transmitted with a key revision block(KRB). The KRB is configured to allow a device being a leaf of a tree to store a leaf key and a limited node key, and a specific effective revision block(EKB) is generated for a group specified by a specific node and distributed thereto so as to limit devices that can be revised. Devices not belonging to the group cannot be decoded and the distribution security of the keys can be ensured. A configuration of distributing a revised master key by the KRB is realized especially in a system using a master key whose generation is managed.